The present invention relates to retractable measuring tapes and more in particular to an improved measuring tape having an improved tape lock mechanism.
Retractable tape measures have been commercially available for many years. These tape measures generally are formed as a steel coiled tape contained within a plastic or metal casing with a coiled spring mounted within the coiled tape to provide a biasing force that tends to automatically recoil and rewind the tape within the casing. Such tape measure devices have been provided with a variety of auxiliary features, such as for example tape lock mechanisms which, when activated, serve to hold the tape in an extended position against the bias of the recoil spring. Such tape lock mechanisms are shown, for example, in U.S. Pat. No. 5,210,956 commonly assigned hereinwith; as well as in U.S. Pat. Nos. 4,976,048; 4,131,244; 4,205,446; 4,153,996; 4,938,430; 5,001,843; and 4,462,160. These various tape lock mechanisms are relatively complex, with some requiring direct connection between a locking blade and a manually operated actuator, and others requiring separate spring members to retract the locking blade when it is desired to retract the tape rule into the casing.
An object of the present invention is to provide an improved tape measure which is relatively simple to manufacture and durable in use.
Another object of the present invention is to provide a retractable tape measure having an improved tape locking mechanism.
Yet another object of the present invention is to provide a tape locking mechanism including integral retraction means.
In accordance with an aspect of the present invention a retractable tape measure is provided which includes a housing or casing having an opening formed therein through which the free end of a coiled tape rule extends. A retraction spring is contained within the casing, generally within the confines of the coiled tape rule, to retract the rule into the casing after it has been extended.
The tape measure of the present invention is selectively locked in an extended position by a locking means or assembly mounted in the casing. The locking assembly includes an actuator member which is movably mounted on the casing for movement between locking and unlocking positions. The tape lock blade is also mounted in the casing for movement between a locking position in which one end of the locking blade is engaged with the tape rule and an unlocking position in which the tape is released for retraction. A connecting link is engaged between the actuator member and the locking blade for transmitting movement of the actuator member to the locking plate. The locking blade includes integrally formed spring means engaged with the casing for applying a biasing force to the locking blade which urges the locking blade against the locking action of the actuator member to move the locking blade to the unlocked position when the actuator member is moved to its unlocked position.